The first prototype used a frame cut from plywood, but the developers moved to some attractive laser-cut Lexan for the final version. The rotating drum was inspired by observing the off-set printing process. It greatly simplifies the build when compared to a flat CNC bed. But including a Z-axis solution that could account for differently sized dots really opens a can of worms. Because of this, the choice was made not to automate that task, but to leave it up to the user. A clickable Sharpie does the marking. When the pen is in place, you click the plunger to hold the felt tip against the paper until a dot of the appropriate size has leeched onto the paper.

Using a human hand as an actuator is a great idea; but I think it could be brought a step further. With a few properly placed electrodes, you could probably automate the plunger-clicking using only existing hardware. You’ll have to check the specs for proper voltages, etc.

So… the only benefit of this, is that you don’t have to choose where to place the pen, just how long to hold it. It still takes you almost the same amount of time to draw a picture. I’d call it useless.

Unless you automated the pen action, then it might make some sense. Like some kind of printer… could be fun to print in “weird” inks like silver, copper, or raspberry.

On the other hand, if the creators wanted an “artsy” interpretation of how we people interact with machines… you could forget the motors, and have someone manually move the pen and drum. Reading the positions off a screen would be a plus, too.